The proposed investigation is a supplement to Grant GM18974-07 and GM18974-08. This project will investigate the structure and function of liver and heart gap junctions. Isolated and in situ junctions will be studied with electron microscopy, x-ray diffraction, SDS-polyacrylamide gel electrophoresis and other techniques of protein and lipid biochemistry. Intact junctions will be studied in whole liver both intact and split with hypertonic dissaccharides. Attempts to understand the uncoupling reaction of gap junctions will center on the mammalian lens as an experimental system.